The carbon in mask is not obtained from coal or coconut but from viscose rayon, mostly derived from wood pulp.
Most carbons used in air purifiers and other filtration media are derivatives of something else, e.g. waste material from coconut husks is a common one. This is often then pressed into another material or turned into pellets.
Cambridge Mask uses a 100% pure activated carbon cloth. It’s made from pure carbon and sourced from pure carbon. The creators of the carbon layer use a very unique method to create the fabric, involving two furnace processes and treatment with silver to help enhance the antiviral properties.